No elected or appointed Etowah County official, including the sheriff, may assume a supernumerary office after the effective date of this amendment. Any person who, on the effective date of this amendment, is entitled to participate in a supernumerary program may continue to participate in that supernumerary program, which shall include the assumption of a supernumerary office according to the terms and conditions of the law which established that supernumerary program. Every elected or appointed Etowah County official, including the sheriff, may participate in the Employees' Retirement System of Alabama upon the same terms and conditions as may be specified by law for any other employee in the same retirement system. Etowah County officials, including the sheriff, holding office at the time of ratification of this amendment shall be eligible to purchase service credit in the Employees' Retirement System for the time the official has served in the current office. No person may participate in both a supernumerary program and the Employees' Retirement System based on the same service. For purposes of this amendment, the words "elected or appointed Etowah County official" do not include a judge, district attorney, legislator, constable, school board member, or any official elected from a judicial circuit.